Method and apparatus for wireless communication on multiple spectrum bands

ABSTRACT

A method and apparatus for simultaneously communicating on at least two carrier frequencies, of which at least one carrier frequency is a licensed band and at least one carrier frequency is an unlicensed band, includes broadcasting an operating status of the unlicensed band to a receiver device, collecting feedback data regarding channel conditions from the receiver device for both the licensed band and unlicensed band, determining, when a bandwidth request is received from the receiver device, whether to use the unlicensed band based on the channel conditions, transmitting an unlicensed band scheduling indication to the receiver device, and communicating with the receiver device using both the licensed band and the unlicensed band according to the transmitted unlicensed band scheduling indication.

PRIORITY

This application is a continuation of, and claims priority under 35U.S.C. § 120 to, U.S. patent application Ser. No. 14/282,673, which wasfiled on May 20, 2014 and was a continuation of, and claimed priorityunder 35 U.S.C. § 120 to, U.S. patent application Ser. No. 14/035,439,which issued as U.S. Pat. No. 8,767,666, was filed on Sep. 24, 2013, andwas a continuation of, and claimed priority under 35 U.S.C. § 120 to,U.S. patent application Ser. No. 13/311,153, which issued as U.S. Pat.No. 8,565,178, was filed on Dec. 5, 2011, and claimed priority under 35U.S.C. § 119(e) to U.S. Prov. Pat. App. No. 61/419,572, which was filedon Dec. 3, 2010, the contents of each of which are incorporated hereinby reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates generally to a wireless communicationsystem, and more particularly, to a wireless communication system fortransmitting and receiving data through both licensed and unlicensedbands.

2. Description of the Related Art

Spectrum bandwidth is a precious resource in wireless communication.Licensed bandwidth includes partitions of bandwidth that are licensed tooperators to provide specific wireless services. Unlicensed bandwidthincludes other partitions of bandwidth that are not specificallyassigned to any operator, and accordingly, any entity may use theseunassigned partitions as long as predefined requirements are met. Eachoperator usually provides authorized services exclusively throughlicensed bands (i.e., authorized services are typically provided throughspectrum that may not be used by any other operators), and thusinter-operator interference may be completely avoided. However, sinceunlicensed bands are open and every operator or personal can access thebandwidth, interference control is very important with respect tounlicensed bands. For example, Wireless Fidelity (WiFi) technologies aredeployed over unlicensed band based on a collision-detection andcontention mechanism. When the number of WiFi users increases, asignificant portion of resources may be wasted on contention andcollision. Further, due to the contention nature of WiFi, Quality ofService (QoS) of the data service may not be guaranteed.

As stated above, licensed bands generally provide services with lessinterference and better QoS than services provided over unlicensedbands, which low-cost services with fair performance in exchange forless reliable or robust channel conditions due to contention andinterference.

In packet-switched data networks, between layers (such as between anapplication layer and a top-most layer), the layers pass Service DataUnits (SDU) across the interfaces. The application layer (or anotherhigher layer) understands the structure of the data in the SDU, but thelower layer at the interface does not understand the structure. Instead,the lower layer at the interface treats the SDU as payload, operating totransport the SDU to the same interface at the destination. In order totransport the SDU, a protocol layer will add, to the SDU, certain datathe protocol layer needs to perform its function. For example, theprotocol layer might add a port number to identify an application, anetwork address to help with routing, a code to identify the type ofdata in the packet of the SDU and error-checking information. All thisadditional information, as well as the original SDU from the higherlayer, constitutes a Protocol Data Unit (PDU) at this layer. When thePDU passes over an interface from a layer that constructed the PDU to alayer that merely delivers the PDU, the PDU becomes a service data unitto that layer. The process of adding addressing and control information(which is also called encapsulation) to an SDU to form a PDU and thepassing of that PDU to the next lower layer as an SDU is repeated untila lowest layer is reached and the data passes over some medium as aphysical signal.

SUMMARY OF THE INVENTION

The present invention is made to address at least the above problems,and/or provide the advantages described below.

An aspect of the present invention to provide apparatus and method forproviding simultaneous communication from a transmitter to a receiverover both licensed and unlicensed bands.

According to an aspect of the present invention, a method, performed bya transmitter device, for simultaneously communicating on at least twocarrier frequencies, of which at least one carrier frequency is alicensed band and at least one carrier frequency is an unlicensed bandis provided. The method includes broadcasting an operating status of theunlicensed band to a receiver device; collecting feedback data regardingchannel conditions from the receiver device for both the licensed bandand unlicensed band; determining, when a bandwidth request is receivedfrom the receiver device, whether to use the unlicensed band based onthe channel conditions; transmitting an unlicensed band schedulingindication to the receiver device; and communicating with the receiverdevice using both the licensed band and the unlicensed band according tothe transmitted unlicensed band scheduling indication.

According to another aspect of the present invention, a method,performed by a receiver device, for simultaneously communicating over atleast two carrier frequencies, of which at least one carrier frequencyis a licensed band and at least one carrier frequency is an unlicensedband is provided. The method includes receiving an operating status ofthe unlicensed band from a transmitter device; transmitting feedbackdata regarding channel conditions to the transmitter device for both thelicensed band and unlicensed band; transmitting a bandwidth request tothe transmitter device; receiving an unlicensed band schedulingindication from the transmitter device; and communicating with thetransmitter device using both the licensed band and the unlicensed bandaccording to received the unlicensed band scheduling information.

According to another aspect of the present invention, a transmitter forsimultaneously communicating on at least two carrier frequencies, ofwhich at least one carrier frequency is a licensed band and at least onecarrier frequency is an unlicensed band is provided. The transmitterincludes a first radio frequency component for operating at the licensedband; a second radio frequency component for operating at the unlicensedband; and a controller for performing at least one of a first operationof broadcasting an operating status of the unlicensed band to a receiverand a second operation of collecting feedback data regarding channelconditions from the receiver for both the licensed band and unlicensedband, determining, when a bandwidth request is received from thereceiver, whether to use the unlicensed band based on the channelconditions, transmitting an unlicensed band scheduling indication to thereceiver, and communicating with the receiver using both the licensedband and the unlicensed band.

According to another aspect of the present invention, a receiver forsimultaneously communicating on at least two carrier frequencies, ofwhich at least one carrier frequency is a licensed band and at least onecarrier frequency is an unlicensed band is provided. The receiverincludes a first radio frequency component for operating at the licensedband; a second radio frequency component for operating at the unlicensedband; and a controller for receiving an operating status of theunlicensed band from a transmitter, transmitting feedback data regardingon channel conditions to the transmitter for both the licensed band andunlicensed band, transmitting a bandwidth request to the transmitter,receiving an unlicensed band scheduling indication from the transmitter,and communicating with the transmitter using both the licensed band andthe unlicensed band.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and advantages of the presentinvention will be more apparent from the following detailed descriptiontaken in conjunction with the accompanying drawings, in which:

FIG. 1 is a diagram illustrating an infrastructure of a system accordingto an embodiment of the present invention;

FIG. 2 is a diagram illustrating a process for Service Data Unit/PacketData Unit (SDU/PDU) fragmentation and reassembly according to anembodiment of the present invention;

FIG. 3 is a diagram illustrating a working flow of a system according toan embodiment of the present invention;

FIG. 4 is a block diagram illustrating a configuration of a base stationaccording to an embodiment of the present invention; and

FIG. 5 is a block diagram illustrating a configuration of a base stationaccording to an embodiment of the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE PRESENT INVENTION

Hereinafter, various embodiments of the present invention are describedwith reference to the accompanying drawings. In the following detaileddescription, same elements will be designated by same reference numeralsalthough they are shown in different drawings. These embodiments aredescribed in sufficient detail to enable those skilled in the art topractice the invention, and it is to be understood that otherembodiments may be utilized and that changes may be made withoutdeparting from the scope of the present invention. The followingdetailed description is, therefore, not to be taken in a limiting sense,and the scope of the present invention is defined by the appendedclaims. Further, in the following description of the present invention,detailed descriptions of known functions and configurations incorporatedherein may be omitted to avoid obscuring the subject matter of thepresent invention.

Hereinafter, embodiments of the present invention are described withreference to a scenario in which data transmission is performed over atleast one licensed frequency band and at least one unlicensed frequencyband.

FIG. 1 is a diagram illustrating an infrastructure of a system accordingto an embodiment of the present invention.

Referring to FIG. 1, a system according to an embodiment of the presentinvention may include a base station 150 and User Element (UE) 100. Thebase station 100 and UE 150 are each equipped with at least one licensedRadio Frequency (RF) and related PHYsical (PHY) layer module. In thepresent example, the licensed air interface is an Institute ofElectrical and Electronics Engineers (IEEE) 802.16/Wimax system, andaccordingly, the UE 100 includes WiMax PHY module 101 while base station150 include WiMax PHY2 module 151. The base station 100 and UE 150 arealso each equipped with at least one unlicensed RF and related PHY layermodule. In the present example, the unlicensed air interface is IEEE802.11/WiFi system, and accordingly, the UE 100 includes WiFi PHY module102 while the base station 150 includes WiFi PHY2 module 152. Accordingto other embodiments of the present invention, the IEEE 802.16/Wimaxsystem of the present example may be replaced with any communicationsystem working on licensed bands, and similarly, the IEEE 802.11/WiFisystem of the present example may be replaced with any communicationsystem working on unlicensed bands. Moreover, according to embodimentsof the present invention, a UE and/or a base station may provide morethan one licensed and/or unlicensed interface.

In the example according to FIG. 1, the transceivers (i.e., base station150 and UE 100) may also have separated Lower Medium Access Control(LMAC) modules for each PHY module to process the data units via theMAC-PHY interface. More specifically, the UE 100 includes a WiMax LMACmodule 103 and a WiFi LMAC module 104 corresponding to the WiMax PHYmodule 101 and the WiFi PHY module 102, respectively. Similarly, theBase Station 150 includes WiMax LMAC2 module 153 and WiFi LMAC2 module154 corresponding to the WiMax PHY2 module 151 and the WiFi PHY2 module152, respectively. However, in the upper MAC layers (i.e., the higherMAC layer 105 of the UE 100 and the higher MAC2 layer 155 of the basestation 150), all the data units moving from the upper MAC layers to thecorresponding lower MACs (i.e., LMACS 103, 104 of the UE 100 and LMAC2s153 and 154 of the base station 150) should be portioned, while the dataunits moving from the lower MACs to the upper MAC layers should bemerged.

Within each of the UE 100 and the base station 150, in upper layersabove the lower MAC layer where the data units are portioned or mergedtoward/from different air interfaces, the system will have the sameinfrastructure as in the legacy system, (i.e., a unified module for eachlayer regardless the processed data units are toward/from different airinterfaces). In FIG. 1, for example, these unified layers include alllayers from the higher MAC layer (i.e., higher MACs 105 and 155) to theInternet Protocol (IP) layer (i.e., IP Control layer 106 and IP Control2layer 156, respectively). The number of layers and terminologycorresponding to each layer may vary from system to system. In aninfrastructure of a communication system, a control plane may beattached across all layers. The control plane may provide functions fortraffic control and scheduling across multiple layers. In a systemaccording to embodiments of the present invention, new functions such astraffic control and scheduling for different air interfaces are added tothe control plane.

FIG. 2 is a diagram illustrating a process for Service Data Unit/PacketData Unit (SDU/PDU) fragmentation and reassembly according to anembodiment of the present invention.

Referring to FIG. 2(a), an IP packet 205 is received from backhaul orgenerated at a transmitter side, which is directed to the UE. In acertain layer N 210, an SDU_(N) 211 is portioned into at least twoparts, such that each part is padded with control information and formsa PDU, such as PDU_(N,1) 212 and PDU_(N,2) 213. According to the presentexample, it is assumed that the SDU_(N) 211 is portioned into two parts,although such a PDU may be portioned into a different number of partsaccording to embodiments of the present invention. The portioned PDUs(i.e., PDU_(N,1) 212 and PDU_(N,2) 213) are then passed down to layerN−1 220, where they are treated as SDUs 221, 222 from the upper layerand further capsuled into PDUs 223, 224 for the next lower layer untilphysical and transmit layer. The data contained in PDU_(N,1) 212 istransmitted using a first air interface 230 (i.e., on the licensedband), while the data contained in PDU_(N,2) 213 is transmitted using asecond air interface 240 (i.e., on the unlicensed band).

Meanwhile, FIG. 2(b) illustrates a corresponding receiver operation.After receiving and decoding information from two separated airinterfaces 250 and 260, two PDUs 271 and 272 are formed for eachrespective interface at layer N−1 270. The layer-respective control headis then removed from the two PDUs 271 and 272 to form two SDUs 273 and274 for the upper layer. At layer N 280, the two SDUs 273 and 274 arereceived from lower layer as PDU_(N,1) 281 and PDU_(N,2) 282. By readingthe control head of the two PDUs 281 and 282, the layer N 280 combinesthese PDUs into one single SDU 283 for an upper layer. The single SDU283 is follows conventional network communication procedures, until thesingle SDU 283 reaches the application layer, or is routed into abackhaul.

According to an embodiment of the present invention, layer N 280 is theupper MAC layer, while layer N−1 270 is the lower MAC layer.

According to embodiments of the present invention, the layers are notrestricted to the layers of the example described with reference to FIG.2, and other such layers in accordance with embodiments of the presentinvention may be any layer in a hierarchical networkmodel/infrastructure.

FIG. 3 is a diagram illustrating a working flow of a system according toan embodiment of the present invention.

Referring to FIG. 3, when a dual-band UE 100 is powered up at step S301,the UE 100 may initially look for either licensed or unlicensed bandsfor an initial access. According to an embodiment of the presentinvention, the UE may initially perform network entry over the licensedband at step S303, since communication over the licensed band isgenerally more reliable than communication over the unlicensed band.Herein “reliable” means network service will generally be expected to bealways on/available. During a capability negotiation procedure, inadditional to conventional capabilities, information corresponding to a“dual licensed/unlicensed band operation” capability should be alsoexchanged. The capability information may further include the operatingcarrier frequency, supported wireless protocol, and supported bandwidth,etc. According to an embodiment of the present invention, thesecapability parameters are predefined so that a plurality of bits can beused to indicate all of the parameters.

At the base station side, if the base station 150 is capable of dualoperation, after initialization corresponding to both the licensed andunlicensed bands in step S302, the base station 150 may broadcast itsunlicensed operation capability and current operating status at stepS305. The capability parameters may include the operating carrierfrequency, supported wireless protocol, supported bandwidth, etc. Thecurrent operating status may include the operating carrier frequency,supported wireless protocol, supported bandwidth, etc. at which the basestation 150 is currently operating. By reading the broadcast informationat step S307, a capable UE 100 can send bandwidth request to the basestation on for the unlicensed band communication if possible.

After the UE 100 is connected to a base station 150, the UE 100 maystart to report channel status information corresponding to bothlicensed and unlicensed bands to the base station 150 at step S309. TheUE 100 may also send a bandwidth request to the base station 150 at stepS309.

The base station 150 may collect feedback on channel conditions and thebandwidth request of the UE 100 on both licensed band and unlicensedbands at step S311. Base on the channel conditions, traffic and QoS ofthe UE 100, as well as the traffic balance between licensed andunlicensed bands, the base station 150 will decide whether asimultaneous licensed and unlicensed communication mode should be turnedon for the UE 100 at step S313.

If the UE 100 is configured to operate in the simultaneous licensed andunlicensed communication mode, the base station 150 sends, at step S315,a command to the UE 100 so that the UE 100 will turn on its function onthe unlicensed band. The UE 100 receives indication and controlinformation from the base station 150 at step S317. The UE 100 and thebase station 150 will start to synchronize and monitor the unlicensedband for its control signaling and respective data traffic at step S318.According to an embodiment of the present invention, the controlsignals, e.g., DownLink/UpLink (DL/UL) resource allocation indications,for both licensed and unlicensed bands, may be transmitted only via thelicensed band; while according to another embodiment of the presentinvention, the control signals for the licensed band are transmitted viathe licensed band, while the control signals for unlicensed bands aretransmitted via respective unlicensed bands.

During the above-described operation, the UE 100 may report channelconditions to the base station 150 periodically or aperiodically basedon configuration settings. The base station 150 will adjust the dualband configuration for each UE based on the information collected. Suchadjustments may include: turning off the licensed/unlicensed bandoperation; and change of the carrier frequency, communication protocol,and/or operating bandwidth for the unlicensed band. The base station 150sends control signals to the UE 100 for these kinds of adjustments.

FIG. 4 is a block diagram illustrating a configuration of a base stationaccording to an embodiment of the present invention.

A base station 150 may include a first radio frequency component 410 foroperating at the licensed band and a second radio frequency component420 for operating at the unlicensed band. The base station may furtherinclude a controller 430 for broadcasting an operating status on theunlicensed bands to a receiver, collecting feedback regarding channelconditions from the receiver on both the licensed band and unlicensedband, deciding on the unlicensed band usage when receiving a bandwidthrequest from the receiver based on the channel condition, transmittingan unlicensed band scheduling indication to the receiver, andcommunicating with the receiver using both the licensed band and theunlicensed band.

The controller 430 of the base station fragments a service data unitinto at least two protocol data units, transmits a first protocol dataunit using the licensed band, and transmits a second protocol data unitusing the unlicensed band. The service data unit fragmentation may beperformed in a Medium Access Control (MAC) layer or a higher layer.

FIG. 5 is a block diagram illustrating a configuration of a base stationaccording to an embodiment of the present invention.

A UE 100 according to an embodiment of the present invention may includea first radio frequency component 510 for operating at the licensed bandand a second radio frequency component 520 for operating at theunlicensed band. The UE may further include a controller 530 forreceiving an operating status regarding the unlicensed bands from atransmitter, transmitting feedback regarding channel conditions to thetransmitter on both the licensed band and unlicensed band, transmittinga bandwidth request to the transmitter, for receiving an unlicensed bandscheduling indication from a transmitter, and communicating with thetransmitter using both the licensed band and the unlicensed band.

The controller 530 of the UE receives a first protocol data unit usingthe licensed band, receives a second protocol data unit using theunlicensed band and combines the at least two received protocol dataunit into at least one service data unit.

Although the present invention has been described above with referenceto certain embodiments thereof, it will be evident that variousmodifications and changes may be made to these embodiments withoutdeparting from the broader spirit and scope of the present invention, asdefined by the appended claims and their equivalents.

What is claimed is:
 1. A method of a user equipment (UE) forcommunication, the method comprising: acquiring information for anunlicensed frequency on a licensed frequency; receiving, on the licensedfrequency from a base station, first control information for a firstresource allocation on the licensed frequency; receiving, on theunlicensed frequency from the base station, second control informationfor a second resource allocation on the unlicensed frequency; receivingfirst data on the licensed frequency based on the first controlinformation; receiving second data on the unlicensed frequency based onthe second control information; generating data packets for the firstdata at a second function corresponding to the licensed frequency, andgenerating data packets for the second data at a second functioncorresponding to the unlicensed frequency; and generating data packetsfor the first data and data packets for the second data at a firstfunction corresponding to the licensed frequency and the unlicensedfrequency.
 2. The method of claim 1, further comprising: receivinginformation for activating the unlicensed frequency on the licensedfrequency.
 3. The method of claim 1, wherein the unlicensed frequency isa wireless fidelity (WiFi) frequency.
 4. A method of a base station forcommunication, the method comprising: transmitting information for anunlicensed frequency on a licensed frequency; transmitting, on thelicensed frequency, first control information for a first resourceallocation on the licensed frequency; transmitting, on the unlicensedfrequency, second control information for a second resource allocationon the unlicensed frequency; generating first data packets for firstdata and second data at a first function corresponding to the licensedfrequency and the unlicensed frequency; generating second data packetsfor the first data based on the first data packets at a second functioncorresponding to the licensed frequency and generating second datapackets for the second data based on the first data packets at a secondfunction corresponding to the unlicensed frequency; transmitting thesecond data packet for the first data on the licensed frequency based onthe first resource allocation; and transmitting the second data packetfor the second data on the unlicensed frequency based on the secondresource allocation.
 5. The method of claim 4, further comprising:transmitting information for activating the unlicensed frequency on thelicensed frequency.
 6. The method of claim 4, wherein the unlicensedfrequency is a wireless fidelity (WiFi) frequency.
 7. A user equipment(UE) for communication, the UE comprising: a transceiver fortransmitting and receiving a signal; and a controller configured to:acquire information for an unlicensed frequency on a licensed frequency,control the transceiver to receive, on the licensed frequency from abase station, first control information for a first resource allocationon the licensed frequency, control the transceiver to receive, on theunlicensed frequency from the base station, second control informationfor a second resource allocation on the unlicensed frequency, controlthe transceiver to receive first data on the licensed frequency based onthe first control information, control the transceiver to receive seconddata on the unlicensed frequency based on the second controlinformation, generate data packets for the first data at a secondfunction corresponding to the licensed frequency, and generate datapackets for the second data at a second function corresponding to theunlicensed frequency, and combine data packets for the first data anddata packets for the second data at a first function corresponding tothe licensed frequency and the unlicensed frequency.
 8. The UE of claim7, wherein the controller controls the transceiver to receiveinformation for activating the unlicensed frequency on the licensedfrequency.
 9. The UE of claim 7, wherein the unlicensed frequency is awireless fidelity (WiFi) frequency.
 10. A base station forcommunication, the base station comprising: a transceiver fortransmitting and receiving a signal; and a controller configured to:control the transceiver to transmit information for a unlicensedfrequency on a licensed frequency, control the transceiver to transmit,on the licensed frequency, first control information for a firstresource allocation on the licensed frequency, control the transceiverto transmit, on the unlicensed frequency, second control information fora second resource allocation on the unlicensed frequency, generate firstdata packets for first data and second data at a first functioncorresponding to the licensed frequency and the unlicensed frequency,split the first data packets to generate second data packets for thefirst data based on the first data packets at a second functioncorresponding to the licensed frequency and to generate second datapackets for the second data based on the first data packets at a secondfunction corresponding to the unlicensed frequency, control thetransceiver to transmit the second data packet for the first data on thelicensed frequency based on the first resource allocation, and controlthe transceiver to transmit the second data packet for the second dataon the unlicensed frequency based on the second resource allocation. 11.The base station of claim 10, wherein the controller controls thetransceiver to transmit information for activating the unlicensedfrequency on the licensed frequency.
 12. The base station of claim 10,wherein the unlicensed frequency is a wireless fidelity (WiFi)frequency.